Natural Herbal products

Viagra dosage (From the Federal Monograph re DOSAGE)

1. “When to take Viagra (on an empty stomach)”
One hour is the best answer. Here’s the official medical information.

1. Dosage Schedules:

take 1 tablet (25mg) by oral route once daily as needed approximately 1 hour before sexual activity
take 2 tablets (50mg) by oral route once daily as needed approximately 1 hour before sexual activity
take 1 tablet (50mg) by oral route once daily as needed approximately 1 hour before sexual activity
take 2 tablets (100mg) by oral route once daily as needed approximately 1 hour before sexual activity
take 1 tablet (100mg) by oral route once daily as needed approximately 1 hour before sexual activity

2. From the Federal Monograph re DOSAGE:

For most men with erectile dysfunction, the recommended initial dose of sildenafil is 50 mg taken as needed approximately 1 hour before anticipated sexual activity. Although sildenafil may be taken anywhere from 4 hours to 30 minutes before sexual activity, peak plasma concentrations usually are achieved within 1 hour (range: 30–120 minutes) when taken on an empty stomach; the erectile response is substantially diminished at 4 hours compared with 2 hours after administration.
Depending on effectiveness and tolerance, the dose subsequently may be increased to a maximum recommended level of 100 mg or decreased to 25 mg.. It currently is recommended that the drug be used no more frequently than once daily; in early studies, more frequent administration (e.g., 3 times daily) was associated with an increased incidence of certain adverse effects (e.g., myalgias). Evidence from dose-ranging studies indicates that erectile response is greater at 50- or 100-mg doses than at 25 mg.

Because geriatric patients may have age-related decreases in renal function and both the pharmacologic and adverse effects of sildenafil may be increased in such patients, consideration should be given to initiating therapy with the drug at a reduced dose of 25 mg in geriatric men 65 years of age and older with erectile dysfunction. Dosage titration should be initiated at 25 mg for patients with hepatic or severe renal impairment with erectile dysfunction (see Dosage and Administration: Dosage in Renal and Hepatic Impairment).

Reduced initial sildenafil dosage also is recommended for patients receiving drugs concomitantly that are potent cytochrome P-450 (CYP) isoenzyme 3A4 inhibitors including certain macrolide anti-infectives (e.g., erythromycin), azole antifungals (e.g., itraconazole, ketoconazole), or certain antiretrovirals (human immunodeficiency virus [HIV] protease inhibitors, delavirdine). For ketoconazole, itraconazole, and erythromycin, the manufacturers recommend that dosage titration be initiated at 25 mg for the treatment of erectile dysfunction and if the dose is well tolerated dosage can be titrated upward cautiously as necessary. The manufacturers of certain other antiretrovirals (amprenavir, atazanavir, delavirdine, fosamprenavir, indinavir, nelfinavir, ritonavir, saquinavir, lopinavir in fixed combination with ritonavir, or tipranavir in combination with low-dose ritonavir) and some experts recommend that sildenafil be used with caution and at a reduced dosage of no more than 25 mg once every 48 hours in patients receiving these antiretrovirals.

Maintenance Dosage.

Oral sildenafil self-medication therapy for erectile dysfunction usually is maintained at the dose that was determined as optimal during initial dosage titration. The optimal maintenance dose should result in an erection that is sufficient for intercourse and maintained after penetration. Adjustments to the initial titrated dose may be required if the underlying cause of erectile dysfunction progresses or if erectile dysfunction improves.

Follow-up monitoring of patients should be performed periodically (e.g., initially at 1–3 months and then annually) to determine patient tolerance, continuing need, and the possible need for dosage adjustment. Data from a large, open-label study in patients with erectile dysfunction of no known organic cause indicate that the dose at the end of a maintenance period (16 weeks) was 25 mg in 11.3% of patients, 50 mg in 29.1% of patients, and 100 mg in 58.1% of patients. In another clinical trial in patients with impotence as a result of complications of diabetes mellitus completing the recommended dose titration, no patients opted to decrease dosage to 25 mg from 50 or 100 mg; at the end of the 12-week study, 93% of patients were receiving the 100-mg dose and 7% were receiving the 50-mg dose. At the end of several large, 12-week, flexible-dose escalation studies with sildenafil (initial dosage of 25–50 mg, then increasing or decreasing to 100 or 25 mg as tolerated or needed) in men with a broad spectrum of erectile dysfunction, 79–98% of the patients were taking 50 or 100 mg. Doses exceeding 100 mg once daily are not recommended because of the increased risk of adverse effects and lack of evidence that such dosages provide increased efficacy compared with a 100-mg dose. (See Uses: Erectile Dysfunction.)

Sildenafil has been shown to remain effective for at least 0.5–3 years in controlled and uncontrolled studies. Although such experience suggests that the drug can be used throughout life in sexually active men if clinically indicated, the likelihood of contraindications to sildenafil therapy (e.g., presence of an underlying cardiovascular disease requiring nitrate therapy) increases with age; in addition, the possibility that prolonged use of the drug could mask the progression of a serious underlying disease must be considered. There currently are no specific limitations to continued sildenafil therapy based on patient age and/or duration of therapy alone.